Re: [LARTC] more on cbq parameters ,further CBQ/tc doc,

[Stef Coene <mailing_staf@belgacom.net>]

>  > On a 100Mbit card connected to a 256kbit line, I used something like:
>  >
>  > tc qdisc add dev eth0 root handle 1: cbq \
>  > 	bandwidth 100Mbit avpkt 1000
>  > tc class add dev eth0 parent 1:0 classid 1:1 cbq \
>  > 	bandwidth 100Mbit rate 256kbit [...]
>  > tc qdisc add dev eth0 parent 1:1 handle 10: cbq \
>  > 	bandwidth 256kbit allot 1514 avpkt 1000
>
> This bandwidth (256 above) is NOT the physical device bandwidth.
>
> Whereas the only thing about bandwidth in
> http://www.ds9a.nl/2.4Routing/HOWTO//cvs/2.4routing/output/2.4routing-9.htm
>l#ss9.4 is:
>   bandwidth
>      The physical bandwidth of your device, also needed for idle time
>   calculations.
>
> I see below that
>
>  >                                   tc-cbq.8
>
> now says, under CLASSES ...
>
>  > bandwidth rate
>  > This is different from the bandwidth specified when creating a CBQ disc.
>  > Only used to determine maxidle and offtime, which are only calculated
>  > when specifying maxburst or minburst. Mandatory if specifying maxburst
>  > or minburst.
>
> Great.  So maybe you should tell us what the value is supposed to mean!
I don't know exactly what the parameter does, but I know that you need to 
specify it like Michael T. Babcock does to get CBQ working.

For the root qdisc this is indeed the physical link bandwidth.  But if you 
attach a qdisc to a class, this is the rate of the class.  I suggest to 
create a bounded class with rate = link bandwidth and attach a qdisc to it.  
Attach all other class to this qdisc and it will work like you want.  Trust 
me, I tried it a lot ;-)


Stef


-- 

stef.coene@docum.org
 More QOS info : http://docum.org/
 Title : "Using Linux as bandwidth manager"
     

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